1. Field of the Invention
The present invention relates to a printer for holding a sheet of label paper wound into a roll, which includes RFID (radio frequency identification) labels, unwinding the held sheet, feeding the unwound sheet, writing information on the labels, and making prints on the labels.
2. Description of Related Art
RFID labels are used for article management employing RFID technique. Bar codes and/or other information can be printed on RFID labels. An antenna and an IC chip are buried in each RFID label so that information can be written on and read from the label.
A conventional printer includes a sheet holder and an RFID reader/writer. The sheet holder holds a sheet of label paper wound into a roll, which consists of a long mount and RFID labels stuck on the mount. The printer unwinds the held sheet of label paper and makes prints on the RFID labels while the unwound sheet is fed. While the unwound sheet is fed, the RFID reader/writer writes information on the RFID labels by communicating by radio with them. The RFID reader/writer may erroneously write information on the RFID labels at the outer periphery of the wound sheet, not the RFID labels of the sheet being fed.
For example, JP2005-335737A discloses a printer fitted with a shield plate in it, on both sides of which two spaces are formed. An RFID reader/writer is fitted in one of the spaces. A sheet of label paper wound into a roll is supported in the other space, which is a nonreceipt space where the electric waves etc. from the RFID reader/writer cannot be received so that erroneous writing can be prevented.
It is necessary to form between the shield plate and a casing a gap through which the sheet of label paper passes. The gap prevents the shield plate from shutting off the two spaces completely from each other. Also, a space is formed around the sheet of label paper wound into a roll in the nonreceipt space. The electric waves emitted from the RFID reader/writer pass through the slight gap into the nonreceipt space and pass the space around the sheet of label paper wound into a roll, and may cause erroneous writing on the IC chips of the RFID labels of the wound sheet.
In particular, in an RFID technique using an UHF for radio communication, which is expected to come into wide use, electric waves are reflected in the printer and easily reach the wound sheet of label paper.
Accordingly, an object of the present invention is to provide a printer which prevents erroneous writing on RFID labels at the outer periphery of a sheet of label paper wound into a roll and supported in the printer.